The present invention relates to a drive train for a motor vehicle, which has a first and a second axle, said drive train having a first drive unit for permanently driving the first axle and an electric drive unit, which is arranged in the region of the second axle and has an electric motor.
A drive train of this kind is known from document DE 103 19 108 A1, for example.
The present invention furthermore relates to a shift clutch arrangement for connecting two rotational bodies that can be rotated relative to one another, for use in a drive train of this kind.
In the motor vehicle sector, especially in the passenger vehicle sector, there is a trend towards all-wheel-drive vehicles, on which both the first and the second axle can be supplied with drive power. In conventional versions, this is accomplished mechanically by way of a transfer case, which distributes the drive power to the first and the second axle.
The transfer case can, for example, have a longitudinal differential, which distributes the drive power in a fixed ratio to the two axles, or a hang-on coupling, by means of which the drive power is fed to one of the two axles only when required.
Another trend in the motor vehicle sector is for hybrid drive trains, which have both an internal combustion engine and an electric machine. One practice that is known in this context (e.g. from the abovementioned document DE 103 19 108 A1) is to drive the first axle by means of the drive unit which has an internal combustion engine and to drive the second axle by means of an electric machine.
In this case, the electric machine is arranged in the region of the second axle and can be aligned parallel to an input shaft of a transverse differential of the second axle.
Systems in which an electric machine is arranged in the region of the first drive unit and the power provided by the electric machine is transmitted to the second axle via a cardan shaft are also known.
In this case, the electric machine is often designed only for a particular speed or torque range.
In the case of shift clutches used in such drive trains, there is the disadvantage, on the one hand, that the said clutches have to be actuated by dedicated motors or by hydraulic means. Moreover, detection of the respective shift state selected is often problematic.